Wireless Communication System

1. A wireless communication system comprising: a wireless communication terminal for Internet Protocol (IP) telephony, which is configured to communicate with a specific communication party and which includes an IP address obtaining unit that obtains a new IP address from a Dynamic Host Configuration Protocol (DHCP) server; a first base station to which the wireless communication terminal wirelessly connects at a time of starting communication with the specific communication party; a second base station to which the wireless communication terminal newly connects after starting the communication with the specific communication party; and a first transfer unit, which is included in the first base station, to transfer information transmitted from the specific communication party to the second base station, a second transfer unit, which is included in the second base station, to transfer information transmitted from the wireless communication terminal to the first base station, wherein each of the first base station and the second base station includes a detection unit to detect an IP telephony call request and an IP telephony disconnect request, each of which is transmittable from the wireless communication terminal, wherein when a handover from the first base station to the second base station occurs while an IP telephone call is not taking place, the IP address obtaining unit obtains the new IP address immediately, wherein when a handover from the first base station to the second base station occurs while an IP telephone call is taking place, the IP address obtaining unit obtains the new IP address after the IP telephone disconnect request is detected, indicating an end of the IP telephone call, and wherein when a handover from the first base station to the second base station occurs while an IP telephone call is taking place, the second base station receives information transmitted from the wireless communication terminal and the second transfer unit transfers the information to the first base station until the wireless communication between the wireless communication terminal and the specific communication party is finished.

2. The wireless communication system according to claim 1 , wherein the first transfer unit transfers the information by IP tunneling.

3. The wireless communication system according to claim 1 , wherein the second transfer unit performs the transferring by IP tunneling.

4. The wireless communication system according to claim 1 , wherein the wireless communication terminal obtains a same network address as that of a network to which the second base station is connected, after the wireless communication between the wireless communication terminal and the specific communication party is finished.

5. The wireless communication system according to claim 1 , wherein the first base station transmits the information from the specific communication party to a new base station which is a changed wireless connection destination, every time a wireless connection destination of the wireless communication terminal is changed.

6. The wireless communication system according to claim 1 , wherein the first base station generates a same provisional identification information as an identification information identifying a network to which the first base station connects, and transmits the provisional identification information to a plurality of neighboring base stations, the wireless communication terminal transmits a retrieval signal of the identification information to retrieve a destination base station of wireless connection among the plurality of neighboring base stations, and a given one of the plurality of neighboring base stations performs communication with the wireless communication terminal through a provisional network corresponding to the provisional identification information, in response to the retrieval signal transmitted from the wireless communication terminal based on the provisional identification information transmitted from the first base station.